Review of dietary polysaccharides for inflammatory bowel disease notes limited clinical evidence

The increasing global burden of inflammatory bowel disease (IBD) has renewed awareness of the limitations and adverse effects of conventional pharmacotherapies, highlighting the need for safe, naturally derived, and mechanistically precise interventions. This review summarizes current understanding of IBD pathogenesis and the biological activities of dietary polysaccharides, with particular emphasis on their diverse protective functions in the gut. Robust preclinical evidence indicates that dietary polysaccharides can markedly alleviate colitis through multiple, interconnected mechanisms. These include reshaping the gut microbial ecosystem and its metabolites—such as short-chain fatty acids, tryptophan-derived indoles, and bile acids—restoring both the mechanical and chemical components of the intestinal barrier, and remodeling cytokine networks while rebalancing key immune cell subsets, including Th17/Treg and M1/M2 macrophages. In parallel, dietary polysaccharides modulate critical inflammatory signaling pathways, notably nuclear factor kappa-B (NF-κB), mitogen-activated protein kinase (MAPK), and NOD-like receptor protein 3 (NLRP3) inflammasome, thereby suppressing excessive intestinal inflammatory activity. Despite these promising experimental findings, clinical evidence remains limited, and important questions regarding structure–activity relationships, in vivo metabolic fate, and long-term safety and efficacy in patients with IBD have yet to be fully addressed. Future research should integrate emerging technologies such as nanotechnology and artificial intelligence to dissect molecular mechanisms in greater depth and to guide the rational design of polysaccharide-based therapeutics, dietary supplements, and functional foods tailored to individual patient profiles, thereby advancing precision nutrition strategies for IBD management.